function [f1,f2,f3,f4,f5] = calc_f12345(a,b,k,z)
%calc_f12345 Summary of this function goes here
%   Detailed explanation goes here
    eakz = exp(-a*k*z);
    ebkz = exp(-b*k*z);
    f1 = k.*( eakz-2*a*b/(1+b^2)*ebkz);
    f2 = k.*(-a*eakz+2*a/(1+b^2)*ebkz);
    f3 = (k.^2).*(-eakz+2*a*b/(1+b^2)*ebkz);
    f4 = (k.^2).*(a^2*eakz-2*a*b/(1+b^2)*ebkz);
    f5 = (k.^2).*(-2*a*eakz+2*a*ebkz);
end

